Some membrane movement and cytoskeletal rearrangement must accompany the locomotion of cells yet little is known about the molecular movements which give rise to these overall structural alterations. This proposal is directed toward examination of the translational movements of plasma membrane and cytoskeletal components during cell motility. To accomplish this, cell surface components will be labeled with fluorescent monoclonal antibodies and fluorescent cytoskeletal proteins will be incorporated into the filanentous structures of the cytoskeleton following their microinjection into the living cells. The changing fluorescent images during motile behavior resulting from the changing distribution of the labeled components will be detected and recorded using computer based ultra-sensitive digitized fluorescence microscopy. Combining this video technology with fluorescence recovery after photobleaching (video-FRAP) will allow detection of flows of both membrane and cytoskeletal components associated with cell movement. The proposed experiments will allow current hypotheses for membrane and cytoskeletal involvement in motility to be tested and will provide new information for the construction of more detailed mechanisms.